Mitsubishi MOTORS Lancer 2005, Workshop Manual Supplement

Page: 62 / 109

MPI <4G63>
ï
Troubleshooting
13D-57
INSPECTION PROCEDURE 23
Low alternator output voltage (approx. 12.3 V) Probable cause
The alternator may be defective, or malfunctions, which are listed in the right column,
may be suspected. D Malfunction of the charging system
(Refer to GROUP 16
ï
Charging System.)
D Short circuit in harness between alternator G terminal
and engine-A/T-ECU
D Malfunction of the engine-A/T-ECU
OK
Check the alternator. (Refer to GROUP
16
ï
Charging System.)
NG
Replace the engine-A/T-ECU.
OK
Check the trouble symptom.
OK
Check the following connectors:
B-18, C-122
NG
Repair
Measureatthealternatorconnectorside
B-26.
D Connect the connector.
(Test harness: MB991519)
D Voltage between 1 (black clip) and
earth
(Engine: Idling)
(Radiator fan: Not operating)
(Head lamp: OFF
o
ON)
(Stop lamp: OFF
o
ON)
(Rear defogger switch: OFF
o
ON)
OK: Voltage rises by 0.2
ï
3.5 V.
NG
Measure at the alternator connector.
B-26
D Disconnect the connector, and
measure at the harness side.
D Disconnect the engine-A/T-ECU
connector.
D Continuity between 1 and earth
OK: No continuity
NG
Check the harness wire between the
alternator and the engine-A/T-ECU con-
nector, and repair if necessary.
INSPECTION PROCEDURE 24
Idling speed is improper when A/C is operating Probable cause
If the engine-A/T-ECU detects that the air conditioner is on, it activates the idle
speed control (ISC) servo to control idle-up operation.
The automatic compressor-ECU judges if the load caused by air conditioner
operation is high or low, and converts it to voltage signal (high or low voltage)
and inputs the signal to the engine-A/T-ECU.
Based on this voltage signal, the engine-A/T-ECU controls the idle-up speed (for
high or low load). D Malfunction of the A/C control system
D Improper connector contact, open circuit or
short-circuited harness wire
D Malfunction of the engine-A/T-ECU
NG
Repair
NG
Replace the engine-A/T-ECU.
NG
Check the A/C system. (Refer to GROUP 55
ï
On-vehicle Service.)
OK
Check the trouble symptom.
Measure at the engine-A/T-ECU connector C-124.
D Connect the connector.
D Voltage between 61 and earth (Engine: at idle, outside air
temperature: 25
_
C or more)
OK: 0
ï
3 V [When A/C is MAX. COOL condition (when
the load by A/C is high)]
System voltage [When A/C is MAX. HOT condition
(when the load by A/C is low)]
OK
Check the following connector:
C-124